Self-Orienting Syringe and Syringe Interface

ABSTRACT

A syringe includes a barrel having a distal end, a proximal end, and a sidewall extending therebetween along a longitudinal axis. At least one engagement member protrudes from a terminal portion of the sidewall in a proximal direction along the longitudinal axis. The at least one engagement member tapers axially in a direction from the distal end toward the proximal end. The at least one engagement member is configured for engagement with a locking mechanism of a fluid injector to releasably lock the syringe with the fluid injector. A taper of the at least one engagement member is configured to rotationally guide the syringe into alignment with the locking mechanism and axially eject the syringe upon rotation of the syringe. The locking mechanism operatively engages the at least one engagement member regardless of an orientation of the syringe about the longitudinal axis relative to the injector.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation under 37 C.F.R §1.53(b) andclaims priority under 35 U.S.C. §120 to U.S. application Ser. No.14/526,395, filed Oct. 28, 2014, the disclosure of which is incorporatedherein by this reference.

BACKGROUND

1. Field of the Disclosure

The present disclosure relates generally to a system including aself-orienting, front-loading syringe for use with a fluid injector and,further, to a connection interface for securing the syringe to the fluidinjector and to a method for loading and removal of the syringe to andfrom the fluid injector.

2. Description of Related Art

In many medical diagnostic and therapeutic procedures, a medicalpractitioner, such as a physician, injects a patient with one or moremedical fluids. In recent years, a number of injector-actuated syringesand fluid injectors for pressurized injection of medical fluids, such asa contrast solution (often referred to simply as “contrast”), a flushingagent, such as saline, and other medical fluids have been developed foruse in procedures such as angiography, computed tomography (CT),ultrasound, magnetic resonance imaging (MRI), positron emissiontomography (PET), and other molecular imaging procedures. In general,these fluid injectors are designed to deliver a preset amount of fluidat a preset pressure and/or flow rate.

In some injection procedures, the medical practitioner places a catheteror a needle connected to tubing, or other fluid delivery connection intoa vein or artery of the patient. The catheter or the tubing is connectedto either a manual or to an automatic fluid injection mechanism.Automatic fluid injection mechanisms typically include at least onesyringe connected to at least one fluid injector having, for example, atleast one powered linear piston. The at least one syringe includes, forexample, a source of contrast and/or a source of flushing fluid. Themedical practitioner enters settings into an electronic control systemof the fluid injector for a fixed volume of contrast and/or saline and afixed rate of injection for each.

The injected contrast and/or saline are delivered to a patient'svasculature through the catheter or needle inserted into the patient'sbody, such as the patient's arm or groin area. A dose of contrast isreferred to as a bolus. Once the bolus of contrast is delivered to thedesired site, that area is imaged using a conventional imagingtechnique, such as angiography imaging or scanning, computed tomography(CT), ultrasound, magnetic resonance imaging (MRI), positron emissiontomography (PET), and other molecular imaging procedures. The presenceof the contrast becomes clearly visible against the background of thesurrounding tissue.

Various front-loading connection interfaces have been developed tofacilitate the loading and removal of the syringe to and from the fluidinjector. In some embodiments, the syringe having a retention feature isinserted into a syringe port on the fluid injector by aligning thesyringe with a corresponding locking feature provided on the fluidinjector. It is often necessary for the medical practitioner to manuallyalign the retention feature of the syringe with the correspondinglocking feature on the fluid injector before the syringe can be loadedonto the injector. In some cases, there are only one or two alignments,such as shown in U.S. Pat. No. 6,336,913. In this syringe, the operatormust manually rotate the syringe to find an alignment that allows thesyringe to engage the fluid injector. It is then necessary for theoperator to manually rotate the syringe relative to the locking featureto create a strong enough engagement for operation of the injector. Inanother syringe disclosed in U.S. Pat. No. 6,652,489, there is no needto rotationally align the syringe or to rotate the syringe forinstallation or engagement. To remove the syringe, the operator mustrotate the syringe at least 45 degrees, and more commonly 90 degrees,about its longitudinal axis to disengage the locking mechanism. Afterrotation, the operator must then physically pull the syringe out of theinjector. In some embodiments, the operator must pull on the syringe atthe same time while rotating the syringe. Such syringe injector featuresrequire additional time and effort to load/remove the syringe from theinjector, resulting in increased time for a medical injection procedure.

Accordingly, there is a need in the art for an improved syringe andinjector attachment, interface, and/or locking feature that allows theoperator to more easily disengage or release the syringe from the fluidinjector, for example to relieve the operator of the effort ofsimultaneously pulling and rotating the syringe. There is a further needin the art for reducing or eliminating the need for rotationallyaligning the syringe with the fluid injector during installation of thesyringe on the fluid injector. While various syringes, syringeconnection interfaces and methods are known in the medical field,improved syringes, connection interfaces between the syringe and thefluid injector and methods for loading and removing the syringe to andfrom the fluid injector continue to be in demand.

SUMMARY OF DISCLOSURE

In view of certain disadvantages of the existing connection interfacesbetween the syringe and the fluid injector, there is a need in the artfor an improved syringe and connection interface between the syringe andthe fluid injector that overcomes the deficiencies of the prior art.There is an additional need for improved methods for loading orinstalling and removing the syringe to and from the fluid injector sothat the syringe does not have to be rotationally aligned about itslongitudinal axis relative to the fluid injector to allow loading orremoval of the syringe to and from the fluid injector.

In one embodiment, a syringe may include a barrel having a distal end, aproximal end, and a substantially circumferential sidewall extendingbetween the distal end and the proximal end along a longitudinal axis.At least one engagement member may protrude from a terminal portion atthe proximal end of the sidewall in a proximal direction along thelongitudinal axis. The at least one engagement member may taper axiallyand/or circumferentially in a direction from the distal end toward theproximal end. The at least one engagement member may be configured forengagement with a locking mechanism of a fluid injector to releasablyposition the syringe within a syringe port of the fluid injector. Ataper of the at least one engagement member may be configured torotationally guide the syringe into alignment with the locking mechanismand axially eject the syringe upon rotation of the syringe.

In another embodiment, a plurality of engagement members may extendabout at least a portion of a circumference of the terminal portion. Theplurality of engagement members may be spaced apart evenly or unevenlyabout the circumference of the terminal portion. In certain embodiments,the at least one engagement member may have a wave form or asubstantially sinusoidal form. In other embodiments, the at least oneengagement member may have a pointed proximal end with at least onetapered surface that extends from the pointed proximal end in a distaldirection along the longitudinal axis to the terminal portion of thesidewall. The pointed proximal end of the at least one engagement membermay have a sharp or rounded point. The at least one tapered surface maybe angled relative to a direction of the longitudinal axis. The at leastone tapered surface may be linear, curvilinear, continuous,discontinuous, or planar. In some embodiments, an encoding device may beprovided on at least a portion of the syringe, such as on at least oneof the at least one engagement member. In certain embodiments, the atleast one engagement member may be monolithically formed with theterminal portion of the sidewall. The at least one engagement member mayhave a circular, triangular, or a polygonal shape. In other embodiments,the at least one engagement member may be separable from the terminalportion of the sidewall.

In another embodiment, a retention flange may protrude radiallyoutwardly from the outer surface of the sidewall relative to thelongitudinal axis and distally of the at least one engagement member forengaging with the locking mechanism of the fluid injector to releasablylock the syringe with the syringe port of the fluid injector. Theretention flange may extend around at least a portion of the outersurface of the sidewall. The retention flange may interact with at leastone deflectable retaining element to retain the syringe within thelocking mechanism. In certain embodiments, the retention flange may havea longitudinal stop surface for limiting a length of a longitudinalinsertion of the syringe into the locking mechanism. A plunger may beslidably disposed within the barrel of the syringe and movable betweenthe proximal end and the distal end. The syringe may further include adrip flange distal to the retention flange for preventing medical fluidfrom dripping from the distal end of the syringe into a syringe port ofa medical injector and fouling the interior workings of the medicalinjector.

In another embodiment, a fluid injection apparatus may include at leastone syringe having a barrel with a distal end, a proximal end, and asubstantially circumferential sidewall extending between the distal endand the proximal end along a longitudinal axis. The barrel may have atleast one engagement member protruding from a terminal portion of theproximal end of the sidewall in a proximal direction along thelongitudinal axis. The at least one engagement member may taper axiallyand/or circumferentially in a direction from the distal end toward theproximal end. The fluid injection apparatus may further include aninjector having an injector housing defining at least one syringe portfor receiving the proximal end of the at least one syringe. A lockingmechanism may be associated with the at least one syringe port forreleasably securing the at least one syringe within the at least onesyringe port. The locking mechanism may be configured for engaging theat least one engagement member of the syringe to releasably position theat least one syringe. A taper of the at least one engagement member maybe configured to rotationally guide the syringe into self-alignment withthe locking mechanism and axially eject the syringe upon rotation of thesyringe within the locking mechanism. In certain embodiments, rotationof the syringe within the locking mechanism disengages the retentionflange from the at least one deflectable retaining element prior toaxially ejecting the syringe.

In yet another embodiment, the locking mechanism may include a housinghaving a central opening configured to receive the proximal end of theat least one syringe. A guide ring may be fixed relative to the housingwith a central axis of the guide ring in coaxial alignment with acentral axis of the housing. The guide ring may have at least one recessextending from an inner circumference of the guide ring to an outercircumference of the guide ring. At least one deflectable retainingelement may be configured to be movably received within the at least onerecess of the guide ring. A lock/release ring may be configured forengagement with the at least one engagement member when the at least onesyringe is inserted into the at least one syringe port. The lock/releasering may be rotatable relative to the housing with a rotation of the atleast one syringe about the longitudinal axis. At least one elasticallyresilient member may be connected at one end to at least a portion ofthe at least one deflectable retaining element to urge the at least onedeflectable retaining element in a radially inward direction todisengage a retention flange on the at least one syringe.

In another embodiment, the at least one deflectable retaining elementmay have a locking lip that is angled relative to the longitudinal axissuch that movement of the at least one syringe in a proximal directioncauses movement of the at least one deflectable retaining element in aradially outward direction. The lock/release ring may include one ormore syringe engagement members that have a complementary shape toreceive the at least one engagement member. The lock/release ring mayinclude at least one guide slot disposed on a top surface to guide amovement of the at least one deflectable retaining element. The at leastone guide slot may include at least one guide track. The at least onedeflectable retaining element may engage the at least one guide track ata first end when the at least one deflectable retaining element is in afirst radial position, and may engage the at least one guide track at asecond end when the at least one deflectable retaining element is in asecond radial position that is different than the first radial position.Lateral edges of the at least one recess may define a travel path forguiding movement of the at least one deflectable retaining element. Atleast a portion of a top surface of the guide ring may define a stopsurface that limits a movement of the at least one syringe in a proximaldirection when the at least one syringe is inserted into the at leastone syringe port.

In a further embodiment, a syringe may include a barrel having a distalend, a proximal end, and a substantially circumferential sidewallextending between the distal end and the proximal end along alongitudinal axis. At least one engagement member may protrude from aterminal portion of the proximal end of the sidewall in a proximaldirection along the longitudinal axis. The at least one engagementmember may taper axially and/or circumferentially in a direction fromthe distal end toward the proximal end. A retention flange may protruderadially outwardly from the outer surface of the sidewall relative tothe longitudinal axis and distally of the at least one engagementmember. The at least one engagement member may be configured forengagement with a locking mechanism of a fluid injector to releasablyposition the syringe within the syringe port of the fluid injector. Ataper of the at least one engagement member may be configured torotationally guide the syringe into self-alignment with the lockingmechanism and axially eject the syringe upon rotation of the syringe. Incertain embodiments, rotation of the syringe within the lockingmechanism disengages the retention flange from the at least onedeflectable retaining element prior to axially ejecting the syringe.

These and other features and characteristics of the syringe and thesyringe connection interface of the fluid injection apparatus, as wellas the methods of operation and functions of the related elements ofstructures and the combination of parts and economies of manufacture,will become more apparent upon consideration of the followingdescription and the appended claims with reference to the accompanyingdrawings, all of which form a part of this specification, wherein likereference numerals designate corresponding parts in the various figures.It is to be expressly understood, however, that the drawings are for thepurpose of illustration and description only. As used in thespecification and the claims, the singular form of “a”, “an”, and “the”include plural referents unless the context clearly dictates otherwise.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic view of a system including a fluid injector andsyringe according to an embodiment of the present disclosure;

FIG. 1B is a perspective view of a syringe according to one embodimentof the present disclosure;

FIG. 2A is an exploded perspective view of a connection interface forsecuring a syringe to a fluid injector according to one embodiment;

FIG. 2B is a cross-sectional assembled view of the connection interfaceshown in FIG. 2A;

FIGS. 3A-3D show cylindrical plan projection views of engagement membersfor guiding/ejecting a syringe into/from a fluid injector according tovarious other embodiments;

FIGS. 4A-4Q show various embodiments of engagement members on a syringe;

FIG. 5A is a schematic diagram of forces on the connection interfaceduring an insertion of a syringe into a fluid injector;

FIG. 5B is a graph of a syringe insertion force as a function of anangle of tapered surfaces at a connection interface for materials withdifferent coefficients of friction μ;

FIG. 6A is a graphical overlay of various profiles of engagement memberson a syringe;

FIG. 6B is a graph of an angular orientation relative to a longitudinalaxis of a sinusoidal engagement member about a circumference of asyringe;

FIG. 7A is a schematic diagram of forces on the connection interfaceduring an ejection of a syringe from a fluid injector;

FIG. 7B is a graph of a slip angle for syringe ejection as a function ofa coefficient of friction between a syringe and a locking mechanism;

FIG. 7C is a graph of a ratio of a rotational force on a syringe duringejection relative to a restoring force of a locking mechanism as afunction of an angle of tapered surfaces at a connection interface;

FIG. 8A is a side cross-sectional view of a coupling configured forconnecting a syringe of the present disclosure to an injector;

FIG. 8B is a perspective view of an adapter configured for connecting asyringe to an injector of the present disclosure; and

FIGS. 9A-9B are perspective views of alternative embodiments ofconnection portions of the coupling shown in FIG. 8A.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

For purposes of the description hereinafter, the terms “upper”, “lower”,“right”, “left”, “vertical”, “horizontal”, “top”, “bottom”, “lateral”,“longitudinal”, and derivatives thereof shall relate to the disclosureas it is oriented in the drawing figures. When used in relation to asyringe, the term “proximal” refers to a portion of a syringe nearest toan injector when a syringe is oriented for connecting to an injector.The term “distal” refers to a portion of a syringe farthest away from aninjector when a syringe is oriented for connecting to an injector. Theterm “radial” refers to a direction in a cross-sectional plane normal toa longitudinal axis of a syringe extending between proximal and distalends. The term “circumferential” refers to a direction around an inneror outer surface of a sidewall of a syringe. The term “axial” refers toa direction along a longitudinal axis of a syringe extending betweenproximal and distal ends. The term “self-orienting” means that a syringeorients itself to the correct orientation within a syringe port duringinsertion without effort by a technician. The terms “axial taper”,“axial tapering”, and “tapering axially” mean an angle of inclination ofat least one virtual or real surface on a syringe in a cylindrical planprojection view in a direction from a distal end toward a proximal endof a syringe. It is also to be understood that specific devices andprocesses illustrated in the attached drawings, and described in thefollowing specification, are simply exemplary embodiments of thedisclosure. Hence, specific dimensions and other physicalcharacteristics related to the embodiments (i.e., aspects, variants,variations, etc.) disclosed herein are not to be considered as limiting.

Referring to the drawings in which like reference characters refer tolike parts throughout the several views thereof, the present disclosureis generally directed to a connection interface between at least onesyringe and a fluid injector.

With reference to FIG. 1A, a fluid injector 10 (hereinafter referred toas “injector 10”), such as an automated or powered fluid injector, isillustrated, which is adapted to interface with and actuate one or moresyringes 12, which may be filled with a medical fluid F, such ascontrast media, saline solution, or any desired medical fluid. Theinjector 10 may be used during a medical procedure to inject the medicalfluid into the body of a patient by driving a plunger 26 of the syringe12 with a piston element. The injector 10 may be a multi-syringeinjector, wherein several syringes 12 may be oriented in a side-by-sideor other relationship and are separately actuated by plungers 26 onrespective linear actuators or piston elements associated with theinjector 10. The injector 10 may be configured to independently deliverone or more fluids from the at least one syringes 12.

The injector 10 may be enclosed within a housing 14 formed from asuitable structural material, such as plastic or metal. The housing 14may be of various shapes and sizes depending on the desired application.For example, the injector 10 may be a free-standing structure configuredto be placed on the floor or may be a smaller design for placement on asuitable table or support frame. The injector 10 includes at least onesyringe port 16 for connecting the at least one syringe 12 to respectivepiston elements. As will be described hereinafter, in some embodiments,the syringe 12 includes at least one engagement member configured forreleasably self-orienting the syringe 12 within the syringe port 16 ofthe injector 10. The at least one engagement member is configured tooperatively engage a locking mechanism provided in the syringe port 16of the injector 10 to facilitate loading or removal of the syringe 12 toand from the injector 10, including ejecting the syringe 12 from thesyringe port 16, as will be described herein. The at least oneengagement member and the locking mechanism together define a connectioninterface for reversibly connecting the at least one syringe 12 to theinjector 10.

A fluid path set 17 may be fluidly connected with at least one of the atleast one syringe 12 for delivering medical fluid F from the at leastone syringe 12 to a catheter (not shown), needle, or other fluiddelivery connection inserted into a patient at a vascular access site.Fluid flow from the at least one syringe 12 may be regulated by a fluidcontrol module (not shown). The fluid control module operates variouspistons, valves and flow regulating structures to regulate the deliveryof the medical fluid, such as saline solution and contrast to thepatient based on user selected injection parameters, such as injectionflow rate, duration, total injection volume, and ratio of contrast mediaand saline. A suitable front-loading fluid injector that may be modifiedfor use with at least one syringe and at least one syringe interface forself-oriented loading and releasable retaining of the at least onesyringe with the fluid injector described herein is disclosed in U.S.Pat. No. 5,383,858 to Reilly et al. which is incorporated by referencein its entirety. Other relevant multi-fluid delivery systems that may beso modified are found in U.S. Pat. No. 7,553,294 to Lazzaro et al.; U.S.Pat. No. 7,666,169 to Cowan et al.; International Patent Application No.PCT/US2012/037491, (published as WO 2012/155035); and United StatesPatent Application Publication No. 2014/0027009 to Riley et al.; all ofwhich are assigned to the assignee of the present application, and thedisclosures of which are incorporated herein by reference.

Having described the general structure and function of the injector 10,the structure of the at least one syringe 12 will now be discussed ingreater detail. With reference to FIG. 1B, the syringe 12 generally hasa substantially cylindrical syringe barrel 18 formed from glass, metal,or a suitable medical-grade plastic. The barrel 18 has a proximal end 20and a distal end 24, with a substantially circumferential sidewall 19extending therebetween along a length of a longitudinal axis 15extending through a center of the barrel 18. The barrel 18 may be madefrom a transparent or translucent material, and may include at least onefluid verification member 11 for verifying a presence of the fluid Fwithin the syringe barrel 18 (shown in FIG. 1A). A nozzle 22 forconnecting to a fluid path 17 extends from the distal end 24 of thebarrel 18. The barrel 18 has an outer surface 21 and an inner surface 23that defines an interior volume 25 configured for receiving the medicalfluid therein. The proximal end 20 of the barrel 18 may be sealed withthe plunger 26 that is slidable through the barrel 18. The plunger 26forms a liquid-tight seal against the inner surface of sidewall 19 ofthe barrel 18 as it is reversibly advanced therethrough. The plunger 26may have a rigid inner element 28 configured for engagement with thepiston of the injector 10. The plunger 26 may further include anelastomeric cover 29 disposed over at least a portion of the rigid innerelement 28. The elastomeric cover 29 is configured to engage the innersurface 23 of the barrel 18 and provide a liquid-tight seal against thesidewall 19 of the barrel 18 as it is reversibly advanced therethrough.

With continued reference to FIG. 1B, the proximal end 20 of the syringe12 is sized and adapted to be inserted in the at least one syringe port16 of the injector 10 (shown in FIG. 1A). In some embodiments, theproximal end 20 of the syringe 12 defines an insertion portion 30 thatis configured to be removably inserted into the syringe port 16 of theinjector 10 while the remaining portion of the syringe 12 remainsoutside of the syringe port 16. As will be described in detailhereinafter, in certain embodiments, the proximal end 20 of the syringe12 includes at least one engagement member 32 adapted to form a lockingengagement with a corresponding locking mechanism in the syringe port 16of the injector 10 for releasably retaining the syringe 12 in thesyringe port 16. The combination of the syringe 12 having the one ormore engagement members 32 with a retention flange 41 and the lockingmechanism 35 (shown in FIG. 2B) of the injector 10 defines a connectioninterface for loading and unloading of the syringe 12 to and from theinjector 10.

According to certain embodiments, a drip flange 36 may extend radiallyoutward from the outer surface 21 of the syringe barrel 18 relative tothe longitudinal axis 15. The drip flange 36 may extend around at leasta portion of the outer circumference of the barrel 18. In oneembodiment, the drip flange 36 is positioned distally along thelongitudinal axis 15 relative to the one or more engagement members 32and distal to the retention flange 41. The drip flange 36 may beconfigured to prevent fluid that drips from the nozzle 22 from enteringthe syringe port 16 on the injector 10. In this manner, the drip flange36 helps reduce the amount of fluid that may enter the syringe port 16and jam or interfere with the connection interface 100 or otherwise foulthe mechanics or electronics of the injector 10. In some embodiments,the drip flange 36 may define an insertion stop surface that delimitshow far the insertion portion 30 of the syringe 12 may be inserted intothe syringe port 16 and/or locking mechanism of the injector 10. Thedrip flange 36 may be formed integrally with the barrel 18 or it may beaffixed or otherwise secured to the outer surface 21 of the barrel 18using, for example, a frictional fit and/or an adhesive, welding, or bymolding. In other embodiments, the drip flange 36 may be formed on theouter surface 21 of the barrel 18 by etching, laser cutting, ormachining.

In other embodiments, the insertion stop surface may be defined by theretention flange 41 positioned closer to the proximal end 20 of thebarrel 18 relative to the drip flange 36, if present. The retentionflange 41 may extend radially outward from the outer surface 21 of thesyringe barrel 18 relative to the longitudinal axis 15. The retentionflange 41 may extend around at least a portion of the outercircumference of the barrel 18 and may be a single continuous flange orone or more discontinuous or intermittent segments. In one embodiment,the retention flange 41 is positioned distally along the longitudinalaxis 15 relative to the engagement member 32. The retention flange 41may be formed integrally with the barrel 18 or it may be affixed orotherwise secured to the outer surface 21 of the barrel 18 using, forexample, a frictional fit and/or an adhesive, welding, or by molding. Inother embodiments, the retention flange 41 may be formed on the outersurface 21 of the barrel 18 by etching, laser cutting, or machining. Theretention flange 41 may be anywhere along the length of the barrel 18 ina distal direction from the one or more engagement members 32. In someembodiments, the retention flange 41 may be formed directly on oradjacent the one or more engagement members 32. The retention flange 41may also be formed by increasing the thickness of the sidewall 19 whilemaintaining a constant inner diameter of the barrel 18 or by increasingthe inner diameter of the barrel 18 and maintaining, decreasing, orincreasing the thickness of the sidewall 19. In this example embodiment,the distal surface of the retention flange 41 forms a retention surface41R (shown in FIG. 2A) which interfaces with one or more retentionsurfaces 78R (shown in FIG. 2B) on one or more retaining elements 78 ofsyringe port 16. At least a portion of the retention flange 41, forexample a proximal surface of retention flange 41, may be tapered orbeveled in a radial direction toward or away from the longitudinal axis15.

With specific reference to FIGS. 2A-2B, a connection interface 100 forloading and removing/ejecting the at least one syringe 12 from the atleast one syringe port 16 of the injector 10 (shown in FIG. 1) is shownin accordance with one embodiment. The syringe 12 and the injector 10include the connection interface 100 having at least one engagementmember 32 provided on the syringe 12 and a corresponding lockingmechanism 35 provided on the syringe port 16 of the injector 10 (shownin FIG. 1). In one embodiment, the at least one engagement member 32 isprovided on the proximal end 20 of the syringe barrel 18. For example,the at least one engagement member 32 may protrude axially in a proximaldirection from the terminal end 27 of the syringe barrel 18. The atleast one engagement member 32 may be formed integrally andmonolithically with the barrel 18 or it may be affixed or otherwisesecured to the terminal end 27 of the barrel 18 using, for example, africtional fit and/or an adhesive, or by welding. In other embodiments,the at least one engagement member 32 may be formed on the terminal end27 of the barrel 18 by etching, laser cutting, machining, or molding. Insome embodiments, the one or more engagement members 32 cooperate withat least a portion of the locking mechanism to self-orient the syringe12 relative to the syringe port 16 such that the syringe 12 may bereleasably locked with the syringe port 16 without physical aligning ofthe syringe or other effort by the user or technician to orient thesyringe 12 with syringe port 16 and/or locking mechanism 35.

In the embodiment shown in FIGS. 2A-2B, the at least one engagementmember 32 is formed as one or more projections that protrude axially ina proximal direction from the terminal end 27 of the syringe barrel 18indicated by a dashed line in FIGS. 1B and 2A-2B. The at least oneengagement member 32 may have the same radial thickness as the sidewall19 of the syringe barrel 18 such that the at least one engagement member32 is substantially continuous with the outer surface 21 and the innersurface 23 (shown in FIG. 1B) of the barrel 18. In other embodiments,the at least one engagement member 32 may protrude radially outward orradially inward relative to the outer surface 21 of the barrel 18. Inaddition, or alternatively, the at least one engagement member 32 mayprotrude radially outward or radially inward relative to the innersurface 23 of the barrel 18. In other embodiments, the at least oneengagement members 32 may be located within the interior of sidewall 19,for example, such that terminal ends of the inner surface 23 and outersurface 21 are substantially even with the proximal end of the at leastone engagement member 32. In certain embodiments, a plurality ofengagement members 32 may be arranged around a circumference of thebarrel 18 in a waveform or sinusoidal form, as detailed herein. Inembodiments where more than two engagement members 32 are provided, theengagement member 32 may be evenly spaced about an outer circumferenceof the barrel 18. For example, in an embodiment with six engagementmembers 32, each engagement member 32 is separated 60 degrees apart fromadjacent engagement members 32. In other embodiments having x engagementmembers 32, each engagement member 32 is separated 360/x degrees apartfrom adjacent engagement members 32, where x is an integer from 1 to360. In other embodiments, the at least one engagement members 32 mayhave unequal angular spacing therebetween about the outer circumferenceof the barrel 18. For example, one or more engagement members 32 maysubtend an angle A (shown in FIG. 1B), which may be more than 60 degreesor less than 60 degrees of the circumference of the barrel 18. In someembodiments, where the at least one engagement members 32 have unequalangular spacing, the spacing and arrangement of the various engagementmembers 32 may be used to encode information regarding the syringeand/or the syringe content, such as manufacturer, lot number, date ofmanufacture, volume, pressure minimum/maximum, compatibility withvarious medical fluids, etc. In some embodiments, each of the engagementmembers 32 may protrude at an equal distance from the terminal end 27 ofthe syringe barrel 18 in a proximal direction. In other embodiments, oneor more engagement members 32 may be longer or shorter than theremaining engagement members 32. Each engagement member 32 issubstantially rigid and free from deflecting in a radial orcircumferential direction during insertion and removal of the syringe 12to and from the syringe port 16. Each engagement member 32 may becontinuous and uninterrupted, or it may be comprised of a plurality ofseparate elements that together define the engagement member 32.

Referring back to FIG. 1B, each of the engagement members 32 may have asubstantially pointed proximal end 37 with a pair of tapered surfaces39A-39B that extend from the proximal end 37 of engagement member 32 ina distal direction along the longitudinal axis 15 toward the terminalend 27 of the syringe 12. The proximal end 37 may have a sharp orrounded point. At least one of the tapered surfaces 39A-39B may beangled axially and/or circumferentially relative to a direction of thelongitudinal axis 15 at an angle B (shown in FIG. 1B). Theaxial/circumferential tapering of the at least one tapered surfaces39A-39B relative to the longitudinal axis 15 may be defined as an angleof inclination of at least one of the tapered surfaces 39A-39B in acylindrical plan projection view in a direction from the distal end 24toward the proximal end 20 of the syringe barrel 18. The taperedsurfaces 39A-39B may be angled at a same or different angle relative tothe longitudinal axis 15. In some embodiments, the tapered surfaces39A-39B may be linear, curved, or a combination thereof. In otherembodiments, the profile of one of the tapered surfaces 39A-39B may thesame or different from the other of the tapered surfaces 39A-39B. Forexample, one of the tapered surfaces 39A-39B may be angled relative tothe direction of the longitudinal axis 15, while the other of thetapered surfaces 39A-39B may be parallel with the direction of thelongitudinal axis 15. In embodiments where at least two engagementmembers 32 are positioned adjacent to each other, the tapered surface39A on one engagement member 32 may transition to the tapered surface39B of each adjacent engagement member 32.

While FIGS. 2A-2B illustrate one non-limiting embodiment of the at leastone engagement member 32, various other shapes are also contemplated(see, for example FIG. 4A-4Q for other non-limiting embodiments). Forexample, the at least one engagement member 32 may have a generallycircular, triangular, square, rectangular, or any other polygonal shape.In each embodiment, the at least one engagement member 32, incombination with the retention flange 41, is configured for forming aself-orienting locking engagement with a corresponding locking mechanism35 in the syringe port 16 of the injector 10 for releasably retainingthe syringe 12 in the syringe port 16, as described herein. For each ofthe embodiments of the engagement member 32, it is also contemplatedthat the number of engagement members 32 used may be varied whileremaining within the scope of the present disclosure. For example, forthe syringe 12 illustrated in FIG. 1B, it is contemplated that only oneengagement member 32 is provided at the terminal end 27 of the syringe12. While a single engagement member 32 may be used, embodiments of thesyringe 12 may have at least two engagement members 32. In someembodiments having even numbers of engagement members 32, the engagementmembers 32 may be located diametrically opposite one another. In otherembodiments, the engagement members 32 are provided adjacent to eachother. The engagement members 32 may be appropriately sized andoptionally may be of different circumferential dimension. Variousnon-limiting embodiments of suitable shapes for the at least oneengagement member 32 are described herein with reference to FIGS. 4A-4Q.

With continuing reference to FIGS. 2A-2B, the syringe port 16 of theinjector 10 has a locking mechanism 35 configured to operatively engagethe at least one engagement member 32 and the retention flange 41 of thesyringe 12. The locking mechanism 35 includes a housing 70 with acentral opening 71 configured to receive the proximal end 20 of thesyringe 12. The housing 70 may be formed as part of the housing 14 ofthe injector 10 (shown in FIG. 1A) or may be attachable to the housing14 to convert an existing injector to include the presently describedlocking mechanism 35. A guide ring 48 may be secured relative to thehousing 70 such the guide ring 48 cannot rotate or move longitudinallyrelative to the housing 70. In one embodiment, the guide ring 48 has abody 72 having one or more tabs 74 (shown in FIG. 2A) extending radiallyoutward from an outer circumference of the body 72. The body 72 of theguide ring 48 may have a continuous annular shape, or it may be formedfrom two or more discrete segments. When installed within the housing70, the one or more tabs 74 engage corresponding one or more grooves 76(shown in FIG. 2A) on an inner sidewall 73 of the housing 70 to preventrotation/longitudinal movement of guide ring 48. In other embodiments,the guide ring 48 may be secured to the housing 70 by other mechanicalfastening arrangements, such as a clip, fastener, or a snap fitarrangement. In further embodiments, the guide ring 48 may be welded,glued, or molded with the housing 70. When installed on the housing 70,a central axis of the guide ring 48 is coaxial with a central axis ofthe housing 70.

With reference to FIG. 2A, the guide ring 48 has one or more firstrecesses 60 that are configured to slidably receive a corresponding oneor more deflectable retaining elements 78. The one or more firstrecesses 60 may be evenly spaced about the body 72 of the guide ring 48.In one embodiment, the one or more first recesses 60 extend from aninner circumference of the guide ring 48 to an outer circumferencethereof. For example, in an embodiment where the guide ring 48 has fourfirst recesses 60, each first recess 60 may be separated 90 degreesapart from the first recesses 60 adjacent on either side. In otherembodiments, the one or more first recesses 60 may be unevenly spacedabout the body 72 of the guide ring 48. The number of first recesses 60on the guide ring 48 may correspond to the number of deflectableretaining elements 78. First recesses 60 may include a groove or pin onthe bottom surface to interface with a pin or groove, respectively, onthe bottom surface of deflectable retaining elements 78 to guidemovement of the deflectable retaining elements 78. The lateral edges ofeach first recess 60 define a radial travel path for guiding themovement of the deflectable retaining elements 78 in a radial directionas the insertion portion 30 of the syringe 12 is inserted into and outof the guide ring 48. At least a portion of a top surface of the guidering 48 may define a stop surface 59 that limits a movement of thesyringe 12 in the proximal direction when the syringe 12 is insertedinto the locking mechanism 35. In one embodiment, the retention flange41 of the syringe 12 engages the stop surface 59 to limit the movementof the syringe 12 in the proximal direction.

With continued reference to FIG. 2A, the locking mechanism 35 furtherincludes one or more deflectable retaining elements 78 configured forsliding in a radial direction relative to the guide ring 48. As detailedfurther herein, each of the one or more deflectable retaining elements78 is radially slidable relative to the guide ring 48 and the housing70, which are both fixed relative to each other. At least one firstelastically resilient member 102 (shown in FIG. 2A), such as a spring,is connected at one end to at least a portion of the one or moredeflectable retaining elements 78 and at the other end to at least aportion of the housing 70. The at least one first elastically resilientmember 102 urges the one or more deflectable retaining elements 78 to afirst position (see FIG. 2B) where a locking lip 80 on the at least onedeflectable retaining element 78 is positioned over the stop surface 59of the guide ring 48 to define a retaining gap 81 (see FIG. 2B). In oneembodiment, by inserting the syringe 12 into the syringe port 16, theretention flange 41 of the syringe 12 engages the locking lip 80 of theat least one deflectable retaining element 78 to deflect the deflectableretaining element 78 radially outward and allow the syringe 12 to beinserted into the locking mechanism 35. The locking lip 80 may beradially angled relative to the longitudinal axis 15 such that movementof the syringe 12 in the proximal direction results in a force having aradially directed component that urges the at least one deflectableretaining element 78 radially outward relative to the syringe 12.Alternatively, the proximal surface of the retention flange 41 may beradially angled or beveled relative to the longitudinal axis 15 suchthat movement of the syringe 12 in the proximal direction results in aforce having a radially directed component that urges the at least onedeflectable retaining element 78 radially outward relative to thesyringe 12. After the retention flange 41 of the syringe 12 clears thelocking lip 80, the at least one deflectable retaining element 78 isrestored to its initial, first position under the urging of the at leastone first elastically resilient member 102. In order to release thesyringe 12 from the locking mechanism 35, the one or more engagementmembers 32 on the syringe 12 engage a lock/release ring 84, and, whenrotated, cause the one or more deflectable retaining elements 78 to moveto a second or open position and allowing ejection of the syringe 12from the locking mechanism 35, as described herein.

With continued reference to FIG. 2A, the locking mechanism 35 mayfurther include the lock/release ring 84 having a generally annularshape. The lock/release ring 84 is configured for engaging one or moreof the at least one engagement member 32 to control selectivepositioning of the syringe 12 within the syringe port 16 to allow forselective locking engagement of one or more deflectable retainingelements 78 with the retention flange 41 of the syringe 12. Thelock/release ring 84 is rotatable relative to the housing 70 with therotation of the syringe 12 about its longitudinal axis 15 by engagementof the at least one engagement member 32 with at least one syringeengagement member 83.

In certain embodiments, the lock/release ring 84 has one or more syringeengagement members 83 extending around an inner circumference of thelock/release ring 84. The one or more syringe engagement members 83 havea complementary shape to that of one or more of the at least oneengagement members 32 on the syringe 12. In one embodiment, the one ormore syringe engagement members 83 are shaped to correspond to the shapeof the at least one engagement members 32 at the terminal end 27 of thesyringe 12. For example, in various embodiments, the one or more one ormore syringe engagement members 83 may have a waveform or sinusoidalshape. The one or more syringe engagement members 83 have interactingsurfaces 85A, 85B along which the tapered surfaces 39A-39B can slide asthe syringe 12 is inserted into or withdrawn from the syringe port 16.The interacting surfaces 85A, 85B are tapered to a sharp or roundedpoint in a distal direction facing the syringe 12. At least one of theinteracting surfaces 85A, 85B may be angled axially relative to adirection of the longitudinal axis 15. The axial tapering of the atleast one interacting surface 85A, 85B relative to the longitudinal axis15 may be defined as an angle of inclination of the interacting surface85A, 85B in a cylindrical plan projection view in a direction toward theproximal end 20 of the syringe 12 when the syringe 12 is inserted intothe syringe port 16. The interacting surfaces 85A, 85B may be angled ata same or different angle relative to the longitudinal axis 15. In someembodiments, the interacting surfaces 85A, 85B may be linear, curved,stepped but defining a substantially linear/curved surface, or acombination thereof. In other embodiments, the profile of one of theinteracting surfaces 85A, 85B may the same or different from the otherof the interacting surfaces 85A, 85B. For example, one of theinteracting surface 85A, 85B may be angled relative to the direction ofthe longitudinal axis 15, while the other of the interacting surface85A, 85B may be parallel with the direction of the longitudinal axis 15.

In embodiments where more than two engagement members 32 are provided onthe syringe 12, the one or more syringe engagement members 83 may beshaped to have a corresponding or complimentary shape and angularspacing such that each of the engagement members 32 engages a respectivesyringe engagement member 83. In other embodiments, the at least oneengagement members 32 may have a multiple of engagement members 32relative to the number of the one or more syringe engagement members 83.In a first position, such as when the syringe 12 is locked within thelocking mechanism 35, each engagement member 32 is aligned with thecorresponding syringe engagement member 83. In a second position, suchas when the syringe 12 is to be removed from the locking mechanism 35,each engagement member 32 is rotationally moved out of alignment withthe corresponding syringe engagement member 83.

With continuing reference to FIG. 2A, the lock/release ring 84 furtherincludes a guide slot 86 to guide the movement of each of thedeflectable retaining elements 78. Each guide slot 86 is disposed on anouter periphery of a top surface 88 of the lock/release ring 84. Eachguide slot 86 has a guide track 90 on which the correspondingdeflectable retaining element 78 is guided between the first position,where the syringe 12 is locked within the locking mechanism 35, and asecond position, where the syringe 12 is unlocked from the lockingmechanism 35. In one embodiment, at least a portion of each deflectableretaining element 78 engages the guide track 90, such as by a pin orother engaging member protruding proximally from the bottom of thedeflectable retaining element 78. In a first position, each deflectableretaining element 78 engages the guide track 90 at a first end 92 suchthat each deflectable retaining element 78 is at its mostradially-inward position. In this position, the retention flange 41 ofthe syringe 12 is retained by the locking lip 80 of the one or moredeflectable retaining elements 78 such that the syringe 12 cannot beremoved from the locking mechanism 35 without rotating the syringe 12relative to its longitudinal axis 15 and engaging the release mechanism.With the rotation of the syringe 12 about its longitudinal axis 15, thelock/release ring 84 is rotated such that each deflectable retainingelement 78 is guided radially outward along the guide track 90 toward asecond end 94, where each deflectable retaining element 78 is at itsmost radially-outward position. In this position, the syringe 12 isremoved from the locking mechanism 35 by ejecting or urging the syringe12 in a distal direction such that the retention flange 41 clears thelocking lip 80 of each deflectable retaining element 78. As the syringe12 is released from the locking mechanism 35, the lock/release ring 84is concurrently rotated to the first position under a restoring actionof a second elastically resilient member 96 that may be secured to abase 98 of the housing 70. In certain embodiments, rotation of thelock/release ring 84 back to the first position under the restoringaction of a second elastically resilient member 96 may provide a lateralforce to the syringe 12 to eject or urge the syringe 12 out of thesyringe port 16.

To insert the syringe 12 into the syringe port 16, the longitudinal axis15 of the syringe 12 is roughly aligned with the longitudinal axis ofthe syringe port 16. Initially, the syringe 12 can be inserted into atop portion of the central opening 71 without rotationally orienting thesyringe 12 about the longitudinal axis 15 relative to the syringe port16. The insertion portion 30 of the syringe 12 is inserted into theopening 71 of the syringe port 16. The syringe retention flange 41 isurged in a proximal direction into contact with the locking lip 80 ofthe at least one deflectable retaining element 78 to deflect it radiallyoutward and allow the syringe 12 to be inserted into the housing 70.Continued proximal movement of the syringe 12 relative the syringe port16 causes the one or more deflectable retaining elements 78 to bedeflected radially outward within the first recesses 60 to a secondposition in which the size of the central opening is increased to allowthe retention flange 41 to pass through. The syringe 12 is advancedproximally into the syringe port 16 such that the one or more taperedsurfaces 39A, 39B on each engagement member 32 come into contact withthe corresponding interacting surfaces 85A, 85B to rotationallyself-orient the syringe 12 such that the peaks of the engagement members32 are received in the valleys of the syringe engagement member 83 onthe syringe port 16 and/or until the retention flange 41 engages thestop surface 59 on the guide ring 48. Under the restoring action of theat least one first elastically resilient member 102, the one or moredeflectable retaining elements 78 are then urged radially from thesecond position to the first position where the locking lip 80 of theone or more deflectable retaining elements 78 may be positioned over theretention flange 41 between the stop surface 59 and a bottom face of thelocking lip 80. In certain embodiments, wherein the drip flange 36 actsas a retention flange 41 the one or more deflectable retaining elements78 may be positioned over the retention flange 41 to retain the dripflange 36 between the stop surface 59 and a bottom face of the lockinglip 80. An audible and/or tactile feedback may be provided by thisaction to indicate to the user that the syringe 12 is locked within thesyringe port 16.

To unlock and release the syringe 12 from the syringe port 16, thesyringe 12 may be rotated about its longitudinal axis 15, for example ina clockwise or counterclockwise direction. Rotation of the syringe 12causes the at least one engagement members 32 to move against the one ormore syringe engagement members 83, thus rotating lock/release ring 84to move the one or more deflectable retaining elements 78 radially tothe second position to release the retention flange 41 from locking lip80. Continued rotation of syringe 12 causes further movement of the atleast one engagement members 32 against and thus axially out ofalignment with the one or more syringe engagement members 83 due to anaxially directed force component imparted on the syringe 12 by themovement of the tapered surfaces 39A-39B along the interacting taperedsurfaces 85A-85B of the syringe engagement members 83. In this manner,the terminal end 27 of the syringe 12 is urged/ejected in a distaldirection by movement of the tapered surfaces 39A-39B along theinteracting tapered surfaces 85A-85B of one or more syringe engagementmembers 83. As described herein, as the syringe 12 is rotated, thelock/release ring 84 is also rotated such that each deflectableretaining element 78 is guided radially outward along the guide track 90toward the second end 94, where each deflectable retaining element 78 isat its most radially-outward position. In this position, due to theaxially directed force created by the interaction of the taperedsurfaces 39A-39B and the interacting tapered surfaces 85A-85B of thesyringe engagement members 83, the syringe barrel 18 and the retainingring 41 are urged distally against the one or more deflectable retainingelements 78 which further urges the one or more deflectable retainingelements 78 radially outward from a first position to a second position.The syringe 12 may be ejected, urged, or popped out of the syringe port16 when the locking lip 80 of the one or more deflectable retainingelements 78 clears the retention flange 41 of the syringe 12 without anyapplied distal force from the user. This tactile and physicalconfirmation of sufficient rotation for unlocking and the ejection orpopping out of the syringe 12 with no further user effort, such as noneed for an axial pull, is a significant improvement over prior artsyringes and syringe injector ports. The ejected syringe 12 can bereadily removed from the locking mechanism 35 by withdrawing the syringe12 in a distal direction. As the syringe 12 is ejected from the lockingmechanism 35, such as when the retaining ring 41 moves distally pastlocking lip 80 and/or the at least one engagement members 32 disengagesfrom the one or more syringe engagement members 83, the lock/releasering 84 is rotated to the first position under a restoring action of thesecond elastically resilient member 96 such that the one or moredeflectable retaining elements 78 are returned to their first, initialposition and the locking mechanism 35 is ready for insertion of a newsyringe 12.

To further discuss the operation of the locking mechanism 35, theretention surfaces of the syringe 12 and the syringe port 16 thatcooperate to retain the syringe 12 in the syringe port 16 once it isengaged are one or more surfaces of the retention flange 41 on thesyringe 12 and the one or more retention surfaces of the deflectableretaining elements 78 on the syringe port 16. The syringe 12 isinitially generally axially aligned and inserted into the opening 71 ofthe syringe port 16. Once partially inserted, the guiding surfaces ofthe syringe 12 and syringe port 16 that cooperate to self-orient orautomatically force the rotational movement to self-orient the syringe12 and the syringe port 16 for installation are the one or more surfaces39A-39B of the engagement members 32 on the syringe 12 and the one ormore tapered guiding surfaces 85A-85B of syringe engagement member 83 ofthe syringe port 16. The opening surfaces of the syringe 12 and syringeport 16 that cooperate to push open the syringe port 16 for theinstallation of the syringe 12 are the one or more bottom surfaces ofthe retention flange 41 on the syringe 12 and one or more of taperedsurfaces of the locking lip 80 on the syringe port 16. The tighteningsurfaces of the syringe 12 and syringe port 16 that cooperate to take upthe mechanical slack or tolerance may include one or more surfaces onthe drip flange 36 on the syringe 12 which push against the outsidehousing or a seal of the syringe port 16 and urge the retention flange41 against the locking lip 80 on the syringe port 16. Alternatively, thetightening force to urge the syringe 12 forward may be provided by aresilient member, such as a second elastically resilient member 96 thatrotationally urges lock/release ring 84 causing a distal force frominteraction of one or more surfaces 39A-39B of the engagement members 32on the syringe 12 and the one or more tapered guiding surfaces 85A-85Bof syringe engagement member 83 or a third resilient member (not shown)that urges the lock/release ring 84 in a distal direction, and whencooperating with a syringe 12 of sufficient length, urges the retentionflange 41 against the locking lip 80. The detachment surfaces of thesyringe 12 and syringe port 16 that cooperate to disengage or remove thesyringe 12 from the syringe port 16 are surfaces of the engagementmembers 32 of the syringe 12 and surfaces of the syringe engagementmember 83 of the syringe port 16. The ejection surfaces of the syringe12 and syringe port 16 that cooperate to create a distally directedforce to urge ejection of the syringe 12 from the syringe port 16 arethe one or more tapered surfaces 39A, 39B on the engagement members 32of the syringe 16 and one or more tapered guiding surfaces 85A-85B ofthe syringe engagement member 83 on the syringe port 16. The rotationalstop surfaces of the syringe 12 and syringe port 16 that cooperate toprevent rotation as a luer connector is screwed onto the syringe 12 areone or more tapered surfaces 39A, 39B on the engagement members 32 ofthe syringe 12 and one or more tapered guiding surfaces 85A-85B of thesyringe engagement member 83 on the syringe port 16, as well as anyfrictional force between the one or more surfaces of the retentionflange 41 of the syringe 12 and one or more retention surfaces of thedeflectable retaining elements 78 of the syringe port 16 and/or betweenthe bottom surface of drip flange 36 and the outside housing or a sealof the syringe port 16.

FIGS. 3A-3D show cylindrical plan projection views of variousembodiments of the at least one engagement members 32 at the proximalend 20 of the syringe 12 and the syringe engagement member 83 of acorresponding syringe port 16 for receiving the proximal end 20 of thesyringe 12. With reference to FIG. 3A, a cylindrical plan projectionview of the interface between the at least one engagement members 32 atthe proximal end 20 of the syringe 12 and the syringe engagement member83 of the lock/release ring 84 is shown in a rotationally alignedorientation for mating the syringe 12 to the syringe port 16. In thisexample embodiment, the at least one engagement members 32 on thesyringe 12 and the corresponding syringe engagement members 83 on thesyringe port 16 are configured as generally sinusoidal projections theproximal end 20 of the syringe 12 having alternating peaks and valleyson the syringe 12 and on the lock/release ring 84. The engagementmembers 32 on the syringe 12 project axially away from the terminal end27 of the syringe 12. If the syringe 12 and the syringe engagementmembers 83 are initially misaligned, the downward or distal force in adirection of arrow A causes a sliding interaction of the taperedsurfaces 39A-39B on the syringe 12 with the corresponding taperedguiding surfaces 85A-85B on the syringe engagement members 83. Suchsliding interaction causes the syringe 12 to rotate and self-orient intothe correct rotational position for alignment with the correspondingtapered guiding surfaces 85A-85B on the syringe engagement members 83and correctly oriented installation of the syringe 12 into the syringeport 16.

FIG. 3B is another cylindrical plan projection view of an alternativeembodiment of the syringe 12. In this embodiment, the engagement members32 extend only partially through the thickness of sidewall 19 of thesyringe barrel 18. In some embodiments, the engagement members 32 may bepositioned on the outside surface 21 of the syringe barrel 18. Theproximal end 37 of the engagement members 32 may terminate at theterminal end 27 of the syringe barrel 18. In other embodiments, theproximal end 37 may extend in a proximal direction relative to theterminal end 27 of the syringe barrel 19, as illustrated, for example,in FIG. 3A. In this manner, the syringe barrel 18 can be made strongerfor a more rigid axial alignment. Additionally, the interior surface ofthe proximal end 20 may be formed as a smooth continuous surface for aneasier installation of the syringe plunger 26. Similarly, thelock/release ring 84 may have syringe engagement members 83 that extendonly through a portion of the radial thickness of the lock/release ring84. FIG. 3C is another cylindrical plan projection view of analternative embodiment in which the engagement members 32 extend onlypartially through the thickness of sidewall 19 of the syringe barrel 18and are positioned on the inside surface of the syringe barrel 12. Acorresponding complementary arrangement of the syringe engagementmembers 83 is present on the lock/release ring 84. In this embodiment,the inside material of the lock/release ring 84 may strengthen theproximal end 20 of the syringe barrel 18 and allow use in higherpressure injections. In some embodiments, the engagement members 32 mayextend through at least a portion of the sidewall 19 of the syringebarrel 18 from the outer surface 21 or the inner surface 23 of thesyringe 12. In other embodiments, the engagement members 32 are formedby creating voids or pockets of appropriate cross sections within thesidewall 19 of the syringe barrel 18. The voids or pockets may beconfigured to interact with complementary syringe engagement members 83present on the lock/release ring 84.

FIG. 3D is a cylindrical plan projection view of an embodiment of anadapter 12B for use with an alternative syringe 12A that cannot itselfdirectly interface with the syringe port 16 and/or locking mechanism 35described herein. According to an embodiment, the adapter 12B may beconfigured, for example as a ring, arc, or other shape, that removablyor non-removably attaches to at least a portion of the terminal end 27Aof the alternative syringe 12A or that may be inserted into lockingmechanism 35 in syringe port 16 to adapt locking mechanism 35 tointeract with the alternative syringe 12A. The adapter 12B may have oneor more engagement members 32B similar to the at least one engagementmembers 32 of syringe 12 described herein. Each engagement member 32Bmay be configured for interacting with a corresponding syringeengagement member 83 of the syringe port 16. The distal side of theadapter 12B may have features or projections that mate withcorresponding features or projections of the syringe 12A. For example,the adapter 12B may have locking members 87B that are configured to bereceived within a corresponding locking member 87A on the syringe 12A,or other locking features that allow syringe 12A to mate with adapter12B and be retained within syringe port 16 and/or locking mechanism 35.

FIGS. 4A-4Q show portions of the cylindrical plan projection views ofvarious embodiments of a portion of the at least one engagement members32 on the syringe 12 and the corresponding embodiments of syringeengagement members 83 on the lock/release ring 84 in syringe port 16.FIGS. 4A-4Q display shapes of alternative embodiments of engagementmembers 32 (labeled as 32A-32Q) and/or syringe engagement members 83(labeled as 83A-83Q) suitable for use with embodiments of the syringe 12and/or lock/release ring 84 in syringe port 16. FIG. 4A shows segmentsof engagement members 32 and 83 of the embodiment described herein withreference to FIG. 3A in a cylindrical plan projection view. FIG. 4Billustrates with dotted lines the approximate surfaces of engagementmembers 32B on the syringe 12 and the corresponding syringe engagementmembers 83B on the syringe port 16 for various embodiments. FIG. 4Cshows an embodiment in which a valley YYC of syringe engagement members83C is extended compared to the surface of engagement member 32C, whileFIG. 4D shows an embodiment in which the surfaces of the syringeengagement member 83D include one or more linear segments to define avalley YYD for receiving engagement member 32D. FIG. 4E illustrates anembodiment in which at least a portion of a valley YYE of 83E has asubstantially rectangular profile, for example, to reduce interferencefrom any debris or other external material while still being capable ofinteracting with engagement member 34E. FIG. 4F illustrates anembodiment in which the syringe engagement member 83F has a flat bottomsurface 83FA with one or more distal projections 83FB which mayselectively contact the engagement members 32F on the syringe 12. Inthis embodiment, the bottom segment of engagement members 32F of syringe12 touch valley sections YYF of the syringe engagement member 83F toallow some rotational slop, gap, or tolerance before rotation of thesyringe 12 will cause contact between tapered surface 32F and one ormore distal projection 83FB and a corresponding rotation of thelock/release ring 84F. In the embodiment shown in FIG. 4G, the bottomsegment of the engagement members 32G do not touch valley sections YYGof the syringe engagement member 83G. Rather, the engagement members 32Gengage at least a portion of the projections 83GB in an operationsimilar to that in FIG. 4F. FIG. 4H shows an embodiment in which boththe engagement members 32H and the syringe engagement members 83H haveat least one segmented linear surface, with the peaks of the syringeengagement members 83H fitting into but preferably not fully filling thevalleys of engagement members 32H on the syringe 12. FIG. 4I showsanother embodiment in which both the engagement members 32I and syringeengagement members 83I are too wide to fit completely into therespective valleys to ensure that the interaction takes place betweenthe angled surfaces of the respective members.

FIG. 4J shows engagement members 32J having a plurality of separatesegments of varying length in the longitudinal direction 15, with thetips or ends of the segments defining the generally sinusoidal profileor other profile described herein required to fit within syringeengagement members 83J. FIG. 4K shows engagement members 32K having aplurality of separate segments of a common length such that a portion ofthe segments may flex radially but not circumferentially when thesyringe 12 is inserted into the syringe port 16. In this embodiment,when the engagement members 32K interact with the syringe engagementmembers 83K, the overlapping projections flex radially relative tosyringe engagement members 83K whereas the non-overlapping projectionson engagement members 32K engage the corresponding syringe engagementmembers 83K as described herein. In an alternative embodiment, syringeengagement members 83 may include spring-loaded balls or fingers whichcan travel circumferentially and group together to match the contours ofengagement members 32 on the syringe 12 and transmit rotational forcesfor activation of the disengagement action. FIG. 4L shows an embodimentwith engagement members 32L having a rod-shaped structure including aprojection substantially parallel with the longitudinal axis 15configured for interacting with the syringe engagement member 83L. Theengagement members 32L have a virtual tapering surfaces 39A-39Bextending from a proximal tip of each engagement member 32L in a distaldirection toward the terminal end 27 of the syringe barrel 18 (shown inFIG. 1B). FIG. 4M shows an embodiment of the engagement members 32Mhaving a rod-shaped structure with a projection that is angled such thatit tapers relative to the longitudinal axis 15 (shown in FIG. 2B). Insome embodiments, the engagement members 32M may be sufficiently rigidto interact with the syringe engagement member 83M. Other embodiments ofengagement member 32 may include a strengthening support between thesyringe terminal end 27 and a middle portion of the projection.Alternatively, the engagement members 32M may flex when rotated fordisengagement and thus provide and added spring force during theejection of the syringe 12 from the syringe port 16.

FIG. 4N shows an embodiment in which the engagement members 32N andsyringe engagement members 83N define a saw tooth pattern havingsubstantially linear tapered surfaces meeting to form a substantiallyangled peak. The engagement members 32N may have equal or unequal peakto peak height or taper angles relative to the syringe engagementmembers 83N or vice versa. FIG. 4O illustrates an embodiment in whichthe frequency of the engagement members 32O on the syringe 12 is greaterthan, for example twice, that of the syringe engagement members 83O onthe lock/release ring 84 in syringe port 16. In other embodiments, thefrequency of the engagement members 32O on the syringe 12 may be aninteger multiple to the frequency of the syringe engagement members 83Oon the syringe port 16. In other embodiments, the frequency of theengagement members 32O on the syringe 12 may be less than the frequencyof the syringe engagement members 83O on the syringe port 16, forexample an integer ratio of the frequency. FIG. 4P illustrates anembodiment in which one or more of the syringe engagement members 83P isabsent. Although not shown, one or more of the engagement members 32P onthe syringe 12 could also be absent. Alternatively, one or more of theengagement members 32P may be absent. FIG. 4Q illustrates an embodimentin which the engagement members 32Q are rounded at their proximal pointand angular at their most distal point, with complementary syringeengagement member 83Q having a substantially pointed peak. While variousnon-embodiments for shapes of the at least one engagement members 32have been represented in FIG. 4A-4Q it is to be understood that suchshapes may be used on the syringe engagement members 83 or on both theengagement members 32 and syringe engagement members 83 according toother embodiments of the present disclosure. Further, combinations ofthe various engagement member shapes may be used on syringe 12,lock/release ring 84 or both. In addition, the engagement members 32 ona syringe 12 may include various combinations of the various embodimentsof the engagement members represented in FIGS. 4A-4Q and equivalents, asdescribed herein. Further, the syringe engagement members 83 on alock/release ring 84 may include various combinations of the variousembodiments of the syringe engagement members represented in FIGS. 4A-4Qand equivalents, as described herein.

FIG. 5A is an illustration of a generalized free body diagram of forcespresent between the tapered surface 39A-39B on the at least oneengagement member 32 and the tapered guiding surface 85A-85B on the atleast one syringe engagement member 83 during insertion of the syringe12 into the syringe port 16. The at least one engagement member 32 onthe syringe 12 interacts with the at least one syringe engagement member83 on the syringe port 16 due to a distally directed force P provided bythe user's hand. Performing a static force analysis on this generalizedinteraction provides an estimate of the force for insertion as afunction of the angle A measured from the axial direction of theinteraction of the two sets of tapered surfaces for various coefficientsof friction μ between the surfaces, as shown in FIG. 5B. In someembodiments, the syringe 12 may be made from a polyethyleneterephthalate (PET) material, while the lock/release ring 84 may be madefrom a polyoxymethylene (POM) material, such as DELRIN™. The coefficientof friction μ of DELRIN™ on another DELRIN™ surface is approximately0.4. The coefficients of friction of various other surfaces can bemeasured and used in the calculations as appropriate. Using this value,a practical limit of the angle A to enable reasonable insertion behavioris approximately 60-65 degrees measured relative to a direction of thelongitudinal axis 15 of the syringe 12. Other practical limits of angleA may be determined for other coefficients of friction to determine theoptimal angle range for tapered surfaces 39A-39B and 85A-85B of the atleast one engagement members 32 and the at least one syringe engagementmembers 83, respectively. For a coefficient of friction of 0.6, an angleless than 50-55° may be used.

FIG. 6A shows an overlay of three different sinusoidal designs for theat least one engagement members 32 of syringe 12. Pattern AA has a peakto peak height of 0.2 inch and a repetition of 16 cycles around a 1.9inch diameter syringe. The barrel wall thickness is relatively smallcompared to the syringe diameter. Pattern BB has a peak to peak heightof 0.2 inch, and a repetition of 6 cycles around the 1.9 inch diametersyringe. Pattern CC has a peak to peak height of 0.4 inch with arepetition of 8 cycles around a 1.9 inch diameter syringe. FIG. 6B showsthe angular orientation relative to the longitudinal axis 15 (shown inFIG. 5A) around a circumference of a 1.9 inch diameter syringe. Theangle may be expressed by a formulaAngle=90−Abs(ArcTan(−(H*N/D)*Sin(N*theta))), where H is the peak to peakheight of the pattern, D is the diameter of the pattern, N is the numberof cycles of repetition around the barrel, and the angle is measuredfrom a direction parallel to the orientation of the longitudinal axis 15shown in FIG. 5A. From this calculation, patterns AA and CC have smallportions where the angle is above 65° and thus may be difficult toinsert.

FIG. 7A is an illustration of a generalized free body diagram of forcesbetween the tapered surface 39A-39B on the at least one engagementmember 32 and the tapered guiding surface 85A-85B on the at least onesyringe engagement member 83 present during release ejection of thesyringe 12 into the syringe port 16. The forces on the syringe 12 arethe normal force N1 and frictional force F1 of the engagement member 32against the engagement member 83, the normal force N2 and frictionalforce F2 of the deflectable retaining elements 78 on the retentionflange 41 as well as the rotational force T applied by the user torotate the syringe and any force D urging the syringe proximallyprovided by the drip flange 36, for example. The syringe engagementmember 83 there has a normal force N3 and frictional force F3 as itslides over base 98 and the restoring force S from the secondelastically resilient members 96. As shown in FIG. 7B, the staticanalysis shows that the angle A is needed for slip at the interfacebetween engagement member 32 and the syringe engagement member 83. For acoefficient of friction μ1 of 0.4, the minimum angle is approximately 20degrees. Thus for angles greater than 20 degrees, there will be slip andupon sufficient motion for the deflectable retaining elements 78 toclear the retention flange 41, the syringe will be ejected from thesyringe port 16. FIG. 7C shows a ratio of the rotational force T torotate the syringe 12 as the restoring force S of the second elasticallyresilient member 96 increases. The ratio is relatively constant as theangle increases, but the ratio increases dramatically at higher angles.In some examples, an angle of at least 30 degrees and less thanapproximately 60 degrees may be used.

In another embodiment, the presence or absence of one or more of the atleast one engagement members 32 around the circumference of the syringebarrel 18 may be used to convey or encode information about the syringe12 or the syringe contents (for example with prefilled syringes). Forexample, such presence or absence of one or more of the at least oneengagement members 32 at specific sites around the circumference of thesyringe 12 can be sensed by various electronic means, for example,optical sensors, mechanical switches, capacitive sensors, and othermeans within the syringe port 16 of injector 10. As an example ofencoded information that may be represented by the presence or absenceof one or more of the at least one engagement members 32, a single codecan be indicative of the absence of engagement member 32, the absence oftwo or more engagement members 32 may provide multiple codes, forexample for different spaces between the engagement members 32.

With reference to FIG. 8A, a coupling 130, including a mounting membertherefor, can be fabricated to be separate from and attachable to thesyringe barrel 18. The coupling 130 can, for example, be configured toaccept the syringe 12 having at least one engagement member 32 describedherein and to adapt the syringe 12 for use with a fluid injector havinga syringe port with a locking mechanism not configured to receive the atleast one engagement member 32. For example, the coupling 130 can adaptthe syringe 12 for use with the fluid injector described in U.S. Pat.No. 5,383,858 or U.S. Pat. No. 6,652,489, or any other fluid injector.In some embodiments, the coupling 130 is releasably connectable to theinjector. In other embodiments, the coupling 130 may be inserted intoand retained in a locking mechanism of the fluid injector. The coupling130 may also be releasably connected or attached to the syringe 12independently of the attachment of the coupling to the injector.

With reference to FIG. 8A, the coupling 130 has a first portion 132configured for receiving the syringe 12 having at least one engagementmember 32 according to an embodiment described herein and a secondportion 134 configured for loading into an injector having a syringeport not configured to receive the syringe 12 having at least oneengagement member 32 according to an embodiment described herein. Thefirst portion 132 may be directly connected and monolithically formedwith the second portion 134. In some embodiments, the first portion 132may be releasably connected to the second portion 134 such that varioussecond portions (shown in FIGS. 9A-9B) may be used with the firstportion 132. With continued reference to FIG. 8A, the first portion 132has a locking mechanism 35 described herein. In various embodiments, thefirst portion 132 of the coupling 130 may be configured for releasablyreceiving the syringe 12 having a corresponding at least one engagementmember 32, as described herein. With reference to FIGS. 9A-9B, thesecond portion 134 of the coupling 130 may have a connection interfaceconfigured for connecting with an injector that would otherwise not becapable of receiving the syringe 12 having at least one engagementmember 32 described herein. FIG. 9A shows the second portion 134configured for use with an engagement mechanism of the injectordescribed in U.S. Pat. No. 5,383,858, while FIG. 9B shows the secondportion 134 configured for use with an engagement mechanism of theinjector described in U.S. Pat. No. 6,652,489. The second portion 134may be configured to interface with various other injectors notexpressly described herein, based on the configuration of the engagementmechanism on the proximal end of the syringe. In some embodiments, thecoupling 130 may have a separate mechanism for engaging and disengagingthe coupling 130 to and from a locking mechanism of the injector.

With reference to FIG. 8B, an adapter 230 may be configured to receive asyringe S not having one or more engagement members 32 described hereinfor removably inserting into an injector having the locking mechanism 35in accordance with one of the embodiments described herein. In variousembodiments, the adapter 230 may be configured for connecting to asyringe S for subsequent installation on an injector. For example, theadapter 230 may be connected to the non-compatible syringe S releasablyor permanently. Such an adapter 230 may have a connection interfacehaving at least one engagement member 32 in accordance with embodimentsdescribed herein. The adapter 230 may be configured for being releasablyconnectable with an injector having a locking mechanism 35 describedherein. The adapter 230 and the syringe S may be connected prior toconnecting to the injector, or the adapter 230 may be connected to theinjector before the syringe S is connected to the adapter 230. Theadapter 230 and syringe S may be removed from the injector after use,with the adapter 230 being disposed of with the syringe S, or beingremoved from the used syringe S and saved for subsequent use with adifferent syringe S.

In one embodiment, a first portion 232 of the adapter 230 may beconfigured for permanently or releasably receiving the syringe S whichis not compatible for use with any of the locking mechanisms 35described herein. In some embodiments, the syringe S may be the syringedescribed in U.S. Pat. No. 5,383,858 or U.S. Pat. No. 6,652,489, or anyother syringe type. The adapter 230 allows the non-compatible syringe Sto engage and be retained by the locking mechanism 35 described herein.In some embodiments, the adapter 230 may have a separate mechanism forengaging and disengaging the syringe S while the adapter 230 remainsconnected to the locking mechanism 35 of the injector 10. The firstportion 232 may also be a cradle or sleeve to hold or retain othersyringes S, for example hand held syringes or syringes having differentretention mechanisms or features and allowing them to engage and beretained by locking mechanisms 35. A second portion 234 of the adapter230 may have at least one engagement member 32 in accordance withembodiments described herein. In some embodiments, the at least oneengagement member 32 may have the configuration described herein withreference to FIGS. 1B-4Q. The second portion 234 of the adapter 230 maybe configured for being releasably connectable with an injector having alocking mechanism 35 described herein. In this manner, variousnon-compatible syringes S may be used with an injector having a lockingmechanism 35 described herein. In various embodiments, the adapter 230may be configured for connecting a pressure jacket (not shown) to theinjector for use in injection procedures requiring high pressure. Forexample, the adapter 230 having the pressure jacket may be configuredfor being releasably connectable with an injector. Such an adapter 230may have a connection interface having at least one engagement member 32in accordance with embodiments described herein or alternatively have aconnection interface that allows non-compatible syringes to be used withthe injector. The adapter 230 may be configured for being releasably,permanently, or semi-permanently connectable with an injector having alocking mechanism 35 described herein and allowing syringes S havingalternate retaining mechanisms to be used with the injector. Onceconnected with the injector, a syringe S may be loaded into the adapter230 or the pressure jacket attached thereto and be retained therein atits proximal or distal end.

In various embodiments, an adapter 230 may be configured for connectinga syringe having some but not all of the features necessary forsubsequent installation into an injector 10 described herein, asdescribed herein with reference to FIG. 3D. The adapter 230 allows asyringe which could not by itself mate or function fully with injectorport 16 to mate and at least perform the retention function with thelocking mechanism 35. By rotating the adapter 230, the syringe and theadapter may be released from the syringe port. Similarly upon insertion,to the adapter 230 may be pushed proximally for engagement with thesyringe. As discussed herein, an adapter can be a ring, such as adapter12B shown in FIG. 3D which interfaces with the injector port 16 and thesyringe 12A. Optionally, the adapter 230 can include additional surfaces(not shown) such as levers, handles, or rings by which the operator canmove one or more aspects of the adapter to release the adapter from thesyringe port and/or release the syringe from the adapter without havingto directly apply a force to or move the syringe.

With reference to FIG. 2A, a system may be provided to transmitinformation from the syringe 12 to the injector 10 (shown in FIG. 1A).In one embodiment, the syringe 12 may be provided with one or moreencoding devices 49 for example, on one or more of the engagementmembers 32. In other embodiments, the one or more encoding devices 49may be provided on the outer surface 21 (shown in FIG. 1B), the innersurface 23 (shown in FIG. 1B), within at least a portion of the sidewall19 (shown in FIG. 1B) of the proximal end 20 of the syringe 12, or onthe plunger 26. In some embodiments, the encoding device 49 may be anoptically readable member, such as a barcode, while in otherembodiments, the encoding device 49 may be an RFID tag, near-fieldcommunication device, or any other suitable encoding device. A pluralityof encoding devices 49 may be disposed around an inner or outercircumference of the syringe 12 and/or the plunger 26. At least onesensor 51 (shown in FIG. 2A) may be provided on the syringe port 16 toread the encoding device 49. In some embodiments, the at least onesensor 51 may be provided on at least one deflectable retaining element78. Examples of information which could be encoded on encoding device 49include, without limitation, dimensions of syringe 12, volume of syringe12, content of the syringe 12 (in the case of a pre-filled syringe),manufacturing information such as lot numbers, dates and tool cavitynumber, recommended contrast media flow rates and pressures, and/orloading/injection sequences. In one embodiment, the presence or absenceof one or more engagement members 32 may serve as the encoding device.For example, one absent engagement member 32 may represent a first code.Two or more adjacent absent engagement members 32 may represent a secondcode. Two or more non-adjacent absent engagement members 32 mayrepresent a third code. Various other combinations of present/absentengagement members 32 may represent various other codes. The presence orabsence of individual engagement members 32 can be determined by theinjector using mechanical switches, electrical material sensors,optically, visually, or by other means know in the sensing art. Thissyringe encoding information is communicated to the injector control forcommunication to the operator and for subsequent use in correctlyprogramming and controlling the injector.

In some embodiments, at least a portion of the injector 10 (shown inFIG. 1A), such as the base 70 of the locking mechanism 35 shown in FIGS.2A and 3A, may have an inner support ring (not shown) that protrudesinto at least a portion of the interior volume 25 of the proximal end 20of the syringe 12. Such a support ring may be removably extendable intoat least a portion of the interior volume 25. The support ring mayprovide radial and axial support to at least a portion of one or moreengagement members 32 and/or the inner sidewall 23 (shown in FIG. 1B) ofthe syringe 12 when the syringe 12 is inserted into the lockingmechanism 35. In embodiments where at least one sensor 51 is provided onthe syringe port 16, such as shown in FIG. 2A, the support ring mayprovide a contrasting surface for detecting the presence or absence ofthe at least one encoding device 49. For example, the support ring mayprovide a contrasting opaque surface against a translucent ortransparent sidewall 19 of the syringe 12 to facilitate the detection ofthe at least one encoding device 49.

Although the disclosure has been described in detail for the purpose ofillustration based on what is currently considered to be the mostpractical and preferred embodiments, it is to be understood that suchdetail is solely for that purpose and that the disclosure is not limitedto the disclosed embodiments, but, on the contrary, is intended to covermodifications and equivalent arrangements. For example, it is to beunderstood that the present disclosure contemplates that, to the extentpossible, one or more features of any embodiment can be combined withone or more features of any other embodiment.

We claim:
 1. A syringe comprising: a barrel having a distal end, aproximal end, and a sidewall extending substantially circumferentiallybetween the distal end and the proximal end along a longitudinal axis;and at least one engagement member protruding from a terminal portion ofthe sidewall in a proximal direction along the longitudinal axis, the atleast one engagement member tapering axially in a direction from thedistal end toward the proximal end, wherein the at least one engagementmember is configured for engagement with a locking mechanism of a fluidinjector to releasably position the syringe with a syringe port of thefluid injector, and wherein a taper of the at least one engagementmember axially ejects the syringe upon rotation of the syringe.
 2. Thesyringe of claim 1, wherein a plurality of engagement members extendabout at least a portion of a circumference of the terminal portion. 3.The syringe of claim 2, wherein the plurality of engagement members arespaced apart evenly about the circumference of the terminal portion. 4.The syringe of claim 1, wherein the at least one engagement member has awave form or sinusoidal form.
 5. The syringe of claim 1, wherein the atleast one engagement member has a pointed proximal tip with at least onetapered surface that extends from the pointed proximal tip in a distaldirection along the longitudinal axis to the terminal portion of thesidewall.
 6. The syringe of claim 5, wherein the pointed proximal tip ofthe at least one engagement member has a sharp or rounded point.
 7. Thesyringe of claim 5, wherein the at least one tapered surface is angledrelative to a direction of the longitudinal axis.
 8. The syringe ofclaim 5, wherein the at least one tapered surface is linear orcurvilinear.
 9. The syringe of claim 5, wherein the at least one taperedsurface is continuous or discontinuous.
 10. The syringe of claim 1,wherein at least one of the engagement members further comprises asecond taper.
 11. The syringe of claim 10, wherein one of the taper andthe second taper of the engagement members rotationally guide thesyringe into alignment with the locking mechanism.
 12. The syringe ofclaim 1, further comprising a flange protruding radially outwardly fromthe outer surface of the sidewall relative to the longitudinal axis anddistally of the at least one engagement member, wherein the flange isconfigured for engaging with the locking mechanism of the fluid injectorto releasably lock the syringe with the syringe port of the fluidinjector.
 13. The syringe of claim 12, wherein the flange extends aroundat least a portion of the outer surface of the sidewall.
 14. A syringecomprising: a barrel having a distal end, a proximal end, and a sidewallextending substantially circumferentially between the distal end and theproximal end along a longitudinal axis; a plurality of engagementmembers protruding from and extending about at least a portion of acircumference of a terminal portion of the sidewall in a proximaldirection along the longitudinal axis, the plurality of engagementmembers each tapering axially in a direction from the distal end towardthe proximal end; and a flange extending around at least a portion ofthe outer surface of the sidewall, the flange protruding radiallyoutwardly from the outer surface of the sidewall relative to thelongitudinal axis and distally of the plurality of engagement members,wherein the flange is configured for engaging with the locking mechanismof the fluid injector to releasably lock the syringe with the syringeport of the fluid injector, wherein the plurality of engagement membersare configured for engagement with a locking mechanism of a fluidinjector to releasably position the syringe with a syringe port of thefluid injector, and wherein a taper of each of the plurality ofengagement members axially ejects the syringe upon rotation of thesyringe.
 15. The syringe of claim 14, wherein at least one taper of theplurality of engagement members interacts with at least one taper of thelocking mechanism to axially eject the syringe from the lockingmechanism upon rotation of the syringe.
 16. The syringe of claim 14,wherein at least a portion of the plurality of engagement memberscomprise a second taper.
 17. The syringe of claim 16, wherein one of thetaper and the second taper of the plurality of engagement membersrotationally guide the syringe into alignment with the lockingmechanism.
 18. A fluid injection apparatus, comprising: at least onesyringe comprising a barrel with a distal end, a proximal end, and asidewall extending substantially circumferentially between the distalend and the proximal end along a longitudinal axis, the barrel having aplurality of engagement members protruding from a terminal portion ofthe sidewall in a proximal direction along the longitudinal axis and aflange extending around at least a portion of the outer surface of thesidewall, wherein the plurality of engagement members each taperingaxially in a direction from the distal end toward the proximal end andthe flange protrudes radially outwardly from the outer surface of thesidewall relative to the longitudinal axis; an injector comprising aninjector housing defining at least one syringe port for receiving the atleast one syringe; and a locking mechanism associated with the at leastone syringe port for securing the at least one syringe within the atleast one syringe port, the locking mechanism configured for engagingthe flange and the plurality of engagement members of the syringe toreleasably position and lock the at least one syringe within the atleast one syringe port, wherein a taper of each of the plurality ofengagement members axially ejects the syringe upon rotation of thesyringe.
 19. The fluid injection apparatus of claim 18, wherein thelocking mechanism further comprises: a lock/release ring comprising oneor more syringe engagement members having a complementary shape forengaging with one or more of the plurality of engagement members whenthe at least one syringe is inserted into the at least one syringe port,the lock/release ring being rotatable relative to the housing with arotation of the at least one syringe about the longitudinal axis,wherein rotation of the lock/release ring disengages the lockingmechanism from the flange on the syringe, allowing the at least onesyringe to axially eject from the at least one syringe port.
 20. Thefluid injection apparatus of claim 18, wherein at least a portion of theplurality of engagement members further comprise a second taper, whereinone of the taper and the second taper of the plurality of engagementmembers rotationally guide the syringe into alignment with the lockingmechanism.